The goal of this proposal is to demonstrate the effectiveness of using magneto-endosymbionts for MRI tracking of transplanted iPS cells in the myocardium. MRI is an important technique for visualizing implanted cells because it is non-invasive and provides high anatomical resolution of cell location. Existing MRI contrast reagents have several critical limitations, when used to label mammalian cells, including an uptake of labeled cells by macrophages leading to the persistent, unspecific MRI signal, and induction of changes in labeled cell function. Magneto-endosymbionts have the potential to overcome these limitations by exerting minimal effects on labeled cells and preventing stable macrophage-dependent signal from occurring. The effectiveness of magneto-endosymbionts as a cell tracking reagent will be assessed by monitoring labeled iPS cell in vitro and in the myocardium and comparing the results with that obtained with currently available techniques. Cell therapies are considered extremely promising for treating cardiovascular disease, including myocardial infarction, congestive heart failure, and coronary artery disease. Recently there has been an intense search for novel techniques that can become effective therapies. Here, we will investigate the viability and engraftment of transplanted magneto-endosymbiont labeled iPS in the heart. Optimizing the tools that can help to monitor transplanted cells in vivo can rapidly accelerate the development of effective cell therapies for cardiovascular disease.